March 28, 2011 - Veil Unveiled

Veil Unveiled Some five to eight thousand years ago, a star exploded in the constellation Cygnus. We don’t know how bright the star was, how long it was visible, or what impact its appearance had on those humans who witnessed it. We do know that the supernova created an energetic shock wave that has expanded, causing the interstellar medium it comes in contact with to glow. A compact circular nebula likely formed right after the explosion, but thousands of years of expansion have turned it into a diffuse, sprawling remnant that now covers an area six times the width of the full Moon. The Veil Nebula, as it is known today, is so diffuse that its isolated components are each given a different designation. Shown here is NGC 6992, also known as the Eastern Veil, one of the largest intact portions of the nebula.